I think that this is not a Steppe Buzzard, even if that is the most common taxa there. The variation of Steppe Buzzard is enormous, that is a well-known fact, but we will have hard time when trying to find, even in huge flocks of Buzzard over Eilat or Batumi, an adult bird which have at the same time this large and blackish flank-patches, this much pale on sparsely marked breast, and round, black carpal patches. Also, the greyish tail with some rather indistinct barring is uncommon in Steppe Buzzard, but the differences in the tail pattern are rather complex, because of the variation in all species. Steppe Buzzard has generally broader dark trailing edge to the wing than Himalayan/Eastern, but in this case that difference is difficult to judge. Many Himalayan/Eastern individuals have more barred bases to outer primaries than this, but it is easy to find exceptions.
Orientalbirdimages seems to be down at the moment, I would have chosen a small sample from there.
Then we should start thinking if we can decide between Himalayan and Eastern. The differences are incompletely known, and many single birds would probably be difficult or impossible even if we knew much more. I don't see any indications why this could not be a Himalayan. The continental Eastern Buzzards are generally somewhat darker, and more reddish, but with lot of exceptions.
I will have a look at the Bangladesh photos later. Without looking I can say that they will be difficult. It is easy to believe, that some vulpinus, some Himalayan birds, some Chinese mountain birds and some long-distance East Asian birds visit that area now and then, and it will be difficult even to decide which is the default.